Petroleum liquids, such as crude oil, typically contain a number of relatively volatile components when produced to surface wellheads via wells extending into subterranean hydrocarbon-bearing formations. Relatively volatile components in the petroleum liquids may include low molecular weight hydrocarbons, such as methane, ethane, propane and butanes, and/or non-hydrocarbon impurities, such as carbon dioxide and hydrogen sulfide. The presence of such components in a petroleum liquid can significantly increase the volatility of the petroleum liquid as evidenced by elevated vapor pressure values.
Relatively volatile components tend to undesirably evolve as vapors from a petroleum liquid having a high vapor pressure when the petroleum liquid is stored or transported at ambient atmospheric pressure. The evolving vapors have a number of deleterious effects. For example, the vapors are highly flammable which creates a safety risk. The vapors also contribute to air pollution, which creates a health risk. The vapors may even be toxic, particularly if they contain hydrogen sulfide, which exacerbates the health risk. As such, petroleum liquids having high vapor pressures are often deemed unstable for storage or transport purposes.
It is apparent that a need exists for an effective method of stabilizing a petroleum liquid produced from a well to diminish the health and safety risks associated with vapors evolving from the petroleum liquid before the petroleum liquid is suitable for storage or transport. Accordingly, it is an object of the present invention to provide an effective process for stabilizing a petroleum liquid. More particularly, it is an object of the present invention to provide a process for stabilizing a petroleum liquid by reducing the vapor pressure of the petroleum liquid. Still more particularly, it is an object of the present invention to provide a process for stabilizing a petroleum liquid by removing volatile components from the petroleum liquid. It is another object of the present invention to provide such a petroleum liquid stabilization process, which enables storing or transporting the petroleum liquid, even at relatively low pressures, with diminished health and safety risks. It is yet another object of the present invention to provide such a petroleum liquid stabilization process, which is can be practiced in a cost-effective manner. It is a further object of the present invention to provide such a petroleum liquid stabilization process, which is can be practiced in an environmentally attractive manner. It is still a further object of the present invention to provide such a petroleum liquid stabilization process, which is can be practiced by means of compact, low-cost, and low-maintenance equipment. It is yet a further object of the present invention to provide such a petroleum liquid stabilization process, which is can be practiced by means of equipment suitable for operation in remote oil field environments. These objects and others are achieved in accordance with the invention described hereafter.